My friends and I (USA~Driver included) first encountered this bug a few months ago, but I did not get around to formally documenting it until today. We first noticed the bug when a submarine was at periscope depth with the floating wire streamed and was detected by a P-3's mast-detection radar. Well, that does not seem too plausible, so we decided to investigate further. We found that submarines at periscope depth with no masts raised and no floating wire streamed were getting detected by the mast-detection radar.

So, today, I recorded this happening in Dangerous Waters for your viewing pleasure. The video has annotations in it that describe what is going on. The video is unlisted, which means only people with this link can see it. I am not at present posting it to my subscribers. I wanted to bring it to you guys first.

First submarine at periscope depth WITH masts raised.
Second submarine at periscope depth WITH NO masts raised.

Both submarines get mast detected.

My question is, should this be happening? This does not seem correct to me. Sure, a submarine can potentially be seen from the air in shallow, clear water, but a submarine at periscope depth with no masts raised getting mast-detected by a P-3? I want to hear your input on this matter, but this seems to be a potentially important issue.

First pass was on 100 ft (below PD). What depth of submarines was second time?

I think it happend because game engine haven't mast detection mechanism and game can only check depth of submarine. So first pass was below PD and "PD mast detection" was not possible. Second pass was at PD depth and game in this case shows You possitions both submarines with text message "Mast Detected, bearing XXX". Personally I likes this solution but range of detection is little bit too long.﻿

Thank you all for the replies. I had hypothesized that this capability is based on the target platform's depth. I have a few follow-up questions:

1) To reiterate USA~Driver, do A.I. aircraft have this capability and will always get a mast detection contact when in range?

2) With the LADAR Mast Detection auto-crew turned off, can the player still detect a submarine's masts manually?

3) Is this set up in such a way that for the Los Angeles, if the player increases depth by 1 foot from periscope depth (or in an Akula, the player increases depth by 1 m from periscope depth), will mast detection no longer work?

These next two points are more philosophical in nature.

4) In a very shallow littoral situation where a submarine has to navigate at periscope depth or shallower, but isn't running with masts raised in order to avoid counter-detection, adversarial platforms will always mast detect them based on what we have discussed here. This seems like this gives ASW platforms an even greater advantage in these types of missions.

5) There is also the situation of deploying special operations forces. The submarine (generally) has to be at periscope depth or shallower in order to accomplish this, but most likely would not have masts raised in order to avoid having its masts counter-detected. With quick launch disabled, this is five minutes of vulnerability. Once the special forces are away, then yes, the ability to be counter-detected should be there. But before that raft appears, there should be no mast detection risk given the submarine does not have masts raised.

Once again, with these last two points, I am not saying one option is correct or incorrect, but just addressing some points of interest than my friends and I have discussed. In a multiplayer situation with surface/airborne ASW assets against submerged threats, the ASW assets already have the advantage because they know that a submerged threat is out there. It seems having a submarine at periscope depth always getting mast detected is just increasing the ASW assets' advantage in a multiplayer match. I am very much interested in hearing your thoughts/opinions on this matter.

1) yes
2) no
3) It is good question but... submarines have different depth for other masts. Which mast is crucial for LADAR?
4) in very shallow water MPA/helo/SUBROC have big problem with dropping torpedoes. They crash to the bottom.
5) this is academic question. I think deploying SF without periscope sweep is not allowed because of procedures
688 H/K have described step by step procedures for SF operations

Pepe, answer are all correct.
From myself I will add only that the detection depth is tied to periscope depth.

In RA, all the depths were converted. As in the original version game, even pop out of the water sail, can not be detected by radar or visual sensors. Even radiation of the radar can not be found, if you are less than 1-2 feet from the working depth of the radar on the American Subs.

And yet - like algorithm is in 688HK engine.
You can see there is such a case - as soon as you go to periscope depth, helicopters immediately find you, even without deployed mast.

PS: In RA, absolutely all platforms have this capability, but are another name of the sensor - underwater visual. And can also detect submarines at periscope depth. But detecting the distance significantly lower, than that of the sensor LADAR.

And - if the launch of special forces so critical, I can try to alter the launch depth slightly below periscope depth, to prevent detection.

Having thought about it for a couple of days I think its enough just being aware of the built in dangers of extended operations at periscope depth. Just don't be there; It was a complete shock at first to be detected at PD as an extended mast with the floating wire. We suspected from the start this was the game and now that it's been confirmed the question now becomes how best to limit exposure. Obviously littoral ops will have to be conducted in waters deeper than PD, and while spec-ops are released at the danger depth, pepe is correct that it wouldn't probably be a good idea to release them with enemy air assets in the immediate vicinity.

I would, however, be in favor of that depth release adjustment (if possible) as a "just in case" safety measure. Having initiated the process of release and waiting only to have some joker on patrol get too close and spoil everything.

This is a new file, to launch special forces from a depth of 67 feet below to 2 feet of periscope depth.
The test sub – 688 improved.
Please note – in the scenario set a trigger the detection of a mast at periscope depth. With the rise to 65 feet (PD), the mast is found from the ship – trigger shoot.